The prognostic and discriminatory utility of the Clinical Frailty Scale and modified frailty Index compared to age

Ben Carter, Victoria Keevil, Atul Anand, Christopher Osuafor, Robert Goudie, Matthew Lowry, Sarah Clunie, Susan Shenkin, Kathryn McCarthy, Jonathan Hewitt, Terry J. Quinn

Research output: Contribution to journalArticlepeer-review


There is no consensus on optimal methods for frailty assessment. We compared prognostic utility of two approaches (modified Frailty Index [mFI], Clinical Frailty Scale [CFS]) in older adults (≥65 years) hospitalised with COVID-19 versus age. Methods: We used a test and validation cohort that enrolled participants hospitalised with COVID-19 between 27th February to 30th June 2020. Multivariable mixed-effects logistic modelling were undertaken, with 28-day mortality as primary outcome. Nested-models were compared between a base model, and age and frailty assessments using likelihood ratio testing (LRT) and an area under the receiver operating curves (AUROC).

Results: The primary cohort enrolled 998 participants from 13 centres, the median age was 80 (range:65-101), 453 (45%) were female and 377 (37.8%) died within 28 days. The sample was rep-licated in a validation cohort of two additional centres (n=672) with similar characteristics. In the primary cohort both mFI and CFS were associated with mortality in base models. There was improved precision when fitting CFS to the base model +mFI (LRT=25.87,p<0.001), however no improvement fitting mFI to the base model +CFS (LRT=1.99,p=0.16). AUROC suggested increased discrimination fitting CFS compared to age (p=0.02) and age +mFI (p=0.03). In contrast, the mFI offered no improved discrimination in any comparison (p>0.05). Similar findings were seen in the validation cohort.

Conclusions: These observations suggest the CFS has superior prognostic value to mFI in predicting mortality following COVID-19. Our data do not support the use of the mFI as a tool to aid clinical decision making and prognosis.
Original languageEnglish
Publication statusAccepted/In press - 21 Aug 2022


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